title: Theoretical exploration of photoisomerization-switchable second-order nonlinear optical responses of two-dimendional λ- and w-shaped polyoxometalate derivatives of dithienylperfluorocyclopentene.
abstract: The switchable second-order nonlinear optical (NLO) properties on two-dimensional (2D) molecules based on Lindqvist-type [Mo6O19](2-) and dithienylperfluorocyclopentene (DTE) have been investigated at density functional theory (DFT) level. The CAM-B3LYP and M06-2X functionals were employed to study the switching behavior on NLO properties by photoisomerization reaction. The βtot value of system 2c (closed-ring form) is 15920.5 au, which is 150.1 times larger than that of the corresponding open-ring form (system 2o). The time-dependent DFT calculations predict that the charge transfer from DTE to polyoxometalate, and DTE intramolecular charge transfer in closed-ring systems effectively improve the static first hyperpolarizability. Furthermore, the Λ-shaped systems possess a larger u value than those of W-shaped systems owing to different orientation for substituent groups.
authors.affiliation: Institute of Functional Material Chemistry, Key Laboratory of Polyoxometalate Science of Ministry of Education, Faculty of Chemistry, Northeast Normal University , Ren Min Street No.5268, Changchun, Jilin 130024, PR China.
authors.forename: Teng-Ying
authors.initials: TY
authors.lastname: Ma
authors.forename: Na-Na
authors.initials: NN
authors.lastname: Ma
authors.forename: Li-Kai
authors.initials: LK
authors.lastname: Yan
authors.forename: Ting
authors.initials: T
authors.lastname: Zhang
authors.forename: Zhong-Min
authors.initials: ZM
authors.lastname: Su